/Engine/Plugins/Runtime/nDisplay/Source/DisplayCluster/Public/Render/Viewport/IDisplayClusterViewportManager.h
Find viewport object and context number by stereoscopic pass index [Game thread func]
[IDisplayClusterViewport](API\Plugins\DisplayCluster\Render\Viewport\IDisplayClusterViewport) * FindViewport ( const int32 StereoViewIndex, uint32 * OutContextNum ) const